The present invention relates to firearms. More specifically, the present invention relates to firearms that can be quickly configured with a minimum of additional parts to fire different calibers of ammunition with improved reliability in harsh environmental and firing conditions.
Currently available firearms have many limitations that can potentially place a user at risk, require long manufacturing times, or be expensive to produce. For example, receivers for firearms that include guidance features, such as internal rails, within a passageway tend to require significant effort to assemble. Often the rails are first manufactured and then attached to the receiver through welding or mechanical fasteners. Alternatively, the receiver is made in halves with integrally formed rails and then the halves are then welded together.
Currently available firearms also present serious safety issues where water is able to fill a barrel or a squib round is fired and the bullet fails to exit the barrel. In these situations, the pressures within the chamber may lead to mechanical failure of the firearm. Often the location of mechanical failure of the firearm is at or near the location of the extractor. A mechanical failure at or near the location of the extractor can render a firearm useless. In a combat situation, a useless firearm places the user at great risk.
Additionally, many currently available firearms that are used in combat and include a rotating bolt eject a spent cartridge upward into the air which may signal the location of the user of the firearm. Thus, the spent cartridge may give away the position of the user to an enemy during combat.
Some currently available firearms are able to fire different calibers of cartridges. However, these firearms all use the same size ejection port for each caliber, which may lead to problems with ejection. For example, the ejection port may be too large so that the spent cartridge is ejected in a random pattern. This random ejection pattern may lead to lost brass as well as user frustration as the brass may be ejected rearward into the user of the firearm. Where the ejection port is functional but slightly too small, the spent cartridge may fail to entirely eject from the firearm which may raise reliability issues.
Similarly, firearms that are able to fire different calibers of cartridges use the same ejector in the same location for all calibers, which can also lead to ejection problems with certain calibers or entirely prevent a firearm designed to fire one caliber from firing larger or smaller cartridges. For example, the ejector for a firearm designed to fire a 5.56 NATO cartridge may be unable to fire a Springfield 30.06 cartridge because the ejector is disposed too close to the barrel.
Currently available firearms for use with multiple calibers may also be difficult to take apart for cleaning or modification. Currently available firearms may also require relatively long periods of time to change from one caliber to another.
Accordingly, a need exists for a firearm that is reliable and durable under harsh conditions and is yet inexpensive to manufacture and requires a minimum of assembly. Furthermore, a need exists for a firearm that is able to reliably extract each round despite fouling and dirt in the receiver. Additionally, a need exists for a firearm that may be used reliably with a variety of differently sized cartridges. A need exists for a firearm that can withstand the pressures within the chamber that result from water or a bullet within the barrel without mechanical failure. A need also exists for a firearm that can eject a spent cartridge in a reliable manner laterally away from the user and not vertically in the air to give the user's position away. Accordingly, a need exists for a firearm that may be quickly changed from firing one caliber to another.